RECLASSIFICATIONS OUT OF ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Effects to Net Income of Amounts Reclassified Out of OCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net interest income	$ 3,758	$ 3,402	$ 3,301
Provision for credit losses	369	302	319
Noninterest income	1,497	1,422	1,678
Noninterest expense	3,352	3,259	3,392
Income before income tax expense	1,534	1,263	1,268
Income tax expense	489	423	403
NET INCOME	1,045	840	865
Amount Reclassified from AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net interest income	63	23	(27)
Noninterest income	(1)	22	18
Noninterest expense	(39)	8	(192)
Income tax expense	38	17	71
NET INCOME	$ 63	$ 20	$ 112